Bright-green Soup

This is an excerpt from Le Menagier de Paris(France, 1393 - Janet Hinson, trans.)
The original source can be found at
David Friedman's website

Bright-green Soup. Cook whatever meat you wish in water, or in a little wine, or in meat stock, wine and bacon to give flavor, then fry your meat, then grind ginger, saffron, parsley and a little sage, if you wish, and egg yolks poured in slowly with a slotted spoon, raw, for the liaison, or ground bread moistened with stock, and put all to boil together with verjuice; and some add cheese, and it is all right.